With the growth of the wireless communications industry, wireless communications protocols become more sophisticated and demanding in their requirements for complex modulation schemes and narrow channel bandwidths. Transmitter output spectrum requirements become more restrictive and less tolerant of spurious transmissions. Third-generation (3G) and later mobile phone standards may be particularly restrictive. Manufacturing variations of RF transmitter circuitry, which is constructed using traditional fabrication techniques, may not meet RF output and efficiency requirements, including output RF spectrum requirements. Adjusting certain parameters of the RF circuitry may enable the RF transmitter circuitry to meet RF output and efficiency requirements; however, traditionally such adjustments have involved calibration of the RF transmitter circuitry after integration into a final product, such as a cell phone, etc. The calibration adjustments are stored in control circuitry in the final product and provided to the RF transmitter circuitry after power-up and before transmitting.
Manufacturers of RF transmitter modules may need to supply RF modules that can be used in a number of different applications. It may be more economical to produce a single type of RF module, which can be configured for a specific application before shipment to an end user. Additionally, if RF transmitter modules could be produced that meet RF output and efficiency requirements for a specific application, then final product calibrations may be simplified or eliminated. Thus, there is a need for an RF transmitter module that can be adjusted to meet output RF and efficiency requirements, configured for a specific application, and can permanently retain the adjustments and configurations.